Signs of this disease generally appear after the age of , when milk drinking declines

Mayo Clinic Q and A: Lactose Intolerance Can Develop at Any Age

DEAR MAYO CLINIC: What would cause someone to become lactose-intolerant later in life? I’m in my 40s and have never had an issue with dairy, but, now, I can’t seem to have it without problems. Do I need to see a doctor to be tested for allergies, or should I just avoid dairy?

ANSWER: Lactose intolerance isn’t a true allergy, and it can develop at any age. In some people, lactose intolerance may be triggered by another medical condition, such as Crohn’s disease. In others, it develops without a specific underlying cause. It would be a good idea to have your condition evaluated by your doctor to confirm that what you’re dealing with truly is lactose intolerance.

Lactose intolerance results from a problem with the carbohydrate lactose, a type of sugar found in dairy products. When you eat or drink dairy products, enzymes in your small intestine digest lactose, so the body can make energy. In people with lactose intolerance, a certain enzyme, called lactase, is missing from the body. When those people eat dairy products, the body has no way to break down the lactose. This leads to fermentation of the sugar in the intestines and triggers symptoms, such as diarrhea, nausea, abdominal cramps, bloating and gas.

Sometimes, lactose intolerance develops when the small intestine’s production of lactase decreases after an illness, injury or surgery involving the small intestine. This is called secondary lactose intolerance. Among the diseases associated with this kind of lactose intolerance are celiac disease, bacterial overgrowth and Crohn’s disease. Treatment of the underlying disorder may restore lactase levels and improve symptoms.

More common than secondary lactose intolerance is primary lactose intolerance. People who develop primary lactose intolerance start life making normal levels of lactase — a necessity for infants, who get all their nutrition from milk. As children replace milk with other foods, lactase production normally decreases. It stays high enough, though, to digest the amount of dairy in a typical adult diet. In primary lactose intolerance, lactase production declines below normal at some point for reasons that are unclear. The low amount of lactase then makes milk products difficult to digest and leads to lactose intolerance symptoms.

Your doctor can confirm a diagnosis of lactose intolerance with a clinical test. One that’s often used is a lactose tolerance test. It assesses your body’s reaction to a dose of lactose. After you consume a drink containing lactose, a sample of your blood is taken to measure glucose levels. If your glucose level does not rise, it means your body isn’t properly digesting and absorbing the lactose.

Alternatively, another test called the hydrogen breath test may be used. This test also requires you to consume a drink that contains high levels of lactose. Your doctor next measures the amount of hydrogen in your breath. Normally, very little hydrogen is detectable. However, if your body doesn’t digest the lactose, the fermentation reaction in your colon releases hydrogen and other gases. Your intestines absorb those gases, and you exhale them. Larger-than-normal amounts of hydrogen measured during this test are a sign that your body isn’t fully digesting and absorbing lactose.

If you have lactose intolerance, there isn’t a way to cure it. The most effective way for people with lactose intolerance to get relief from symptoms is to lower the amount of dairy products they eat. You may be able to use dairy products that have reduced levels of lactose or are lactose-free. Some people who have lactose intolerance benefit from taking lactase enzyme supplements, as well.

If test results do not point to lactose intolerance, your doctor may recommend additional tests to check for another condition that could be causing your symptoms, such as a milk allergy, intestinal disorders or other problems within your digestive tract. — Dr. Rohit Divekar, Allergic Diseases, Mayo Clinic, Rochester, Minnesota

Although lactose intolerance usually begins when you’re around age two, it isn’t until you reach adolescence or adulthood that the symptoms typically appear for many people. In fact, the condition is more likely to appear in adults, and the older you get, the more likely it is that you’ll discover you’re lactose intolerant.

Lactose intolerance is a condition best described as the inability to process lactose, the sugar found in milk and milk products. To properly digest lactose, you need a sufficient amount of an enzyme called lactase, which is produced in the lining of your small intestines. The lactase breaks down the milk-based sugars into galactose and glucose. These forms of sugar then get absorbed into your bloodstream and used for energy.

Just because you have a lactase deficiency, doesn’t necessarily mean you’ll ever develop lactose intolerance. Even people who do have the condition don’t always develop digestive symptoms. Lactose intolerance develops over time, and the symptoms become much more noticeable as you age. The main symptoms include:

  • Gas
  • Bloating
  • Nausea, often accompanied by vomiting
  • Diarrhea
  • Abdominal cramps

Lactose intolerance can be difficult to diagnose because its symptoms mimic those of other digestive disorders such as Irritable Bowel Syndrome and GERD. Your Manhattan gastroenterologist may ask you to eliminate milk products for a period of time to see if your symptoms subside. Other tests that can help detect the condition include:

  • Hydrogen breath testing
  • Lactose intolerance testing

Other Causes

In addition to advancing age, other causes of lactose intolerance can include small intestine injury. Digestive disorders such as Crohn’s disease, an overgrowth of intestinal bacteria, and Celiac disease can lead to lactose intolerance.

Your ethnicity also plays a factor. Hispanic, Asian, American Indian and African Americans are more prone to lactose intolerance.


There is no cure for lactose intolerance, though dietary changes can help mitigate your symptoms. Follow your doctor’s orders regarding diet and supplements. You need to make sure you get sufficient calcium if you forgo milk in all its forms, though most adults with lactose intolerance can handle small amounts. Here are some diet tips:

  • Switch to soy milk or lactose-free dairy products. They are now widely available in grocery stores.
  • Eat and drink small, four-ounce portions of dairy to decrease the risk of gastrointestinal issues.
  • Read labels to find hidden lactose. It may be listed as milk byproducts, whey and dry milk powder. Some medications also are made with lactose.
  • Experiment with other forms of dairy. Hard cheeses and live cultured yogurt, for example, often don’t produce significant symptoms.
  • Try over-the-counter lactase drops

Before you begin any self-treatment, however, get a professional diagnosis from a New York City gastroenterologist to ensure you don’t have a more serious condition and to work out a plan for staying healthy while avoiding milk.

Book an appointment more information on how NYC Gastroenterologist Dr. Shawn Khodadadian can help to treat lactose intolerance.

Ask the experts

I would appreciate some information about lactose intolerance, from which I seem to be suffering. I am 76 years old, and have never had any digestive problems, until now.

Doctor’s response

The sugar present in milk and milk products is called lactose. Our small intestine makes an enzyme that is needed to break down this sugar and is called lactase. A significant portion of the world population is either lacking or has insufficient amounts of this enzyme. This is particularly true amongst the Asians and Black Africans and Afro- Americans. As we age, the amount of this enzyme in our intestines is gradually depleted. As a result we can tolerate smaller amounts of milk or milk products (low-fat milk or non-fat milk contain the same amount of lactose as regular milk). The symptoms of lactase deficiency (therefore lactose intolerance) include gas, abdominal cramping and/or diarrhea when a person takes in more dairy products than his/her lactase can handle.

Treatment options include taking the enzyme lactase pills or drops (Lactaid, Lactrase, etc.) before and during a meal rich in lactose. Most groceries also carry low lactose milk which is another way to enjoy dairy. Yogurt is another good source of a low lactose dairy product, as long as the container indicates it has live culture. Anyone that is lactose intolerant should make it point to carefully check the ingredients of all packaged or pre-processed foods as they may contain unsuspected lactose. The three words to look for are milk, lactose, and whey.

Remember, optimal results depend on accurate diagnosis. Please consult your doctor to make sure that you are not suffering from other digestive disease that can mimic lactose intolerance.


What Is the Treatment?

Only a doctor can tell if your symptoms come from IBS or lactose intolerance. They usually diagnose IBS based on the symptoms you describe. For lactose intolerance, you’ll need to give a little more information, such as:

  • Your family history
  • A physical exam
  • A hydrogen breath test. Undigested lactose in your body gives off high levels of hydrogen. During the test, you drink a beverage that has lactose, then blow air into a special bag. A lab tests your breath to look for the gas.

IBS symptoms can come and go, but it’s a condition you’ll have for the rest of your life. There is no cure for it. But you can use a few different strategies to manage how you feel. Changes to your diet and tools to handle stress may help ease your symptoms. Medications like anti-diarrhea drugs or laxatives can make you feel better, too. It’s important to work with a doctor to find the approach that works for you.

There is also no cure for lactose intolerance, but it usually helps to avoid milk, cheese, and other dairy foods. Some people with the condition can handle small amounts of them, and others have to cut them out completely. Your doctor or dietitian can help you figure out the right diet and suggest supplements that may help. There are lactase enzyme replacements available which can be taken with food, but they have varying degrees of benefit.


Lactose is the sugar found in milk and dairy products such as cheese and yogurt. After eating dairy products that contain this sugar, usually lactase, a digestive enzyme of the small intestine, helps to breakdown this complex sugar into two simple sugars, glucose and galactose. These simple sugars are then absorbed in the small intestine and ultimately reach the blood stream where they act as nutrients. The enzyme lactase is located in the lining of the small intestine known as the intestinal villi.

In addition to milk and dairy products such as ice cream, yogurt and cheese, lactose can be found in bread and baked goods, processed breakfast cereals, instant potatoes, some soups and non-kosher lunch meats, candies, dressings and mixes for pancakes and biscuits. Lactose is also the sugar found in breast milk and standard infant formulas. Therefore almost all babies are able to digest and absorb this sugar and it serves as their primary dietary sugar.


Because lactose is not digested properly in the small intestine of individuals who are lactose intolerant, it passes whole into the large intestine or colon. Upon reaching the colon it is broken down by the normal colon bacteria. This breakdown results in the production of carbon dioxide and hydrogen gases. The gas production can lead to the following common symptoms:

  • Abdominal distension and pain
  • Excess burping
  • Loud bowel sounds
  • Excess gas and diarrhea following ingestion of lactose.
  • Watery and explosive bowel movements
  • Urgency with bowel movements, which means that children feel that they have to get to the bathroom immediately or they will have an accident.

The symptoms of lactose intolerance can start during childhood or adolescence and tend to get worse with age. The severity of symptoms is usually proportional to the amount of the milk sugar ingested with more symptoms following a meal with higher milk sugar content.

Although eating lactose-containing products will result in discomfort for someone who is lactose intolerant, they are not at risk of developing more serious intestinal disease because of long-term lactose malabsorption. The only exception to this would be for babies who are born with primary lactase deficiency or children with secondary lactase deficiency as discussed below.


Primary Lactase Deficiency: This condition is very rare and occurs when babies are born with a deficiency or absence of the enzyme lactase. Babies inherit this condition by getting one gene that causes this problem from each of their parents, even though both parents may be lactose tolerant. These babies require a specialized formula with another type of sugar such as sucrose (present in table sugar), which they are able to digest.

Secondary Lactase Deficiency: The most common cause of temporary lactose intolerance in infants and young children is infection that affects the gastrointestinal tract and can damage the lining of the small intestine.

Rotavirus and Giardia are two common organisms that cause damage to the surface of the small intestine resulting in temporary lactose intolerance. Older infants and young children will commonly be infected by a rotavirus. The symptoms of rotavirus infection include vomiting, diarrhea (frequent watery stools), and fever. Giardia is a parasite that is found in well water and fresh water from lakes and streams. Treatment of giardia infection with antibiotics will resolve the lactose intolerance.

Secondary lactase deficiency can also be due to Celiac disease, which is an intolerance to gluten, the protein found in wheat, rye, barley and other grains. Crohn disease, an inflammatory condition that can affect any part of the gastrointestinal tract can lead to secondary lactase deficiency as well. Once each of these conditions is treated, the lactase deficiency will resolve. The lactose intolerance usually resolves within three to four weeks when the lining of the intestines returns to normal.

Acquired Lactase Deficiency: Many individuals acquire lactose intolerance as they get older. It is estimated that approximately one half of adults in the United States have acquired lactase deficiency. This condition is due to a normal decline in the amount of the enzyme lactase present in the small intestine as we age. Although lactose is an important part of the diet in infants and young children it represents only 10% of the carbohydrate (sugar) intake in adults. However, individuals who are lactose intolerant may not be able to tolerate even small amounts of this sugar in their diet.

Lactose intolerance occurs more frequently in certain families. One of the most important factors affecting the rate of developing lactose intolerance is an individual’s ethnic background. Approximately 15% of adult Caucasians, and 85% of adult African Americans in the United States are lactose intolerant. The rate of lactose intolerance is also very high in individuals of Asian descent, Hispanic descent, Native Americans and Jewish individuals.


Lactose intolerance is diagnosed by a simple test called a hydrogen breath test. After a overnight fast before the test, an individual breathes into a bag and then drinks a specified amount of the milk sugar as a syrup. In adults this corresponds to the amount of milk sugar in a quart of milk. Subsequent breath samples are taken for up to three hours. The breath that they exhale into the bag is analyzed to determine its hydrogen content. During the course of the test individuals who are lactose intolerant will have an increase in the amount of hydrogen that they exhale. If the values for hydrogen increase above a certain value the diagnosis of lactose intolerance is made. Patients who are lactose intolerant may also develop their typical symptoms during the test.

In younger children or in children who cannot tolerate the breath test, removal of lactose from the diet and possible supplementation with lactase can be done for 2-4 weeks to see if this improves the symptoms.


The best treatment of lactose intolerance is a combination of dietary modification and taking a supplement to aid in digestion of lactose. Individuals who are lactose intolerant should meet with a dietician to review the sources of lactose in their diet. Some reduction in the daily lactose consumption is usually required. When an individual is going to be eating a food that contains lactose they should take a commercially available non-prescription lactase supplement at the time of lactose ingestion. This type of supplement can be taken throughout the day whenever lactose is ingested. Some individuals will be less lactose intolerant and therefore will be able to tolerate comparatively larger amounts of lactose. Alternatives to milk for lactose intolerant individuals include products such as soy milk. If an individual is restricting their milk/ dairy intake it is important to ensure adequate supplementation of calcium and Vitamin D in the diet. This is especially important for pediatric patients and women.

Recommended daily calcium intakes:
1-3 years of age 500 mg
4-8 years of age 800 mg
9-24 years of age 1300 mg
Age 25 and above 800-1000 mg
Pregnant and nursing women 1200 mg

Author(s) and Publication Date(s)

Marsha H. Kay, MD, The Cleveland Clinic, Cleveland, OH, and Vasundhara Tolia, MD, Children’s Hospital of Michigan, Detroit, MI – Published September 2004.

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What Is Lactose Intolerance?

Lactose intolerance is the inability to digest a sugar called lactose that is found in milk and dairy products.

Normally when a person eats something containing lactose, an enzyme in the small intestine called lactase breaks it down into simpler sugar forms called glucose and galactose. These simple sugars are then easily absorbed into the bloodstream and turned into energy — fuel for our bodies.

People with lactose intolerance do not produce enough of the lactase enzyme to break down lactose. Instead, undigested lactose sits in the gut and gets broken down by bacteria, causing gas, bloating, stomach cramps, and diarrhea.

Lactose intolerance is fairly common and seems to affect guys and girls equally. Little kids are less likely to have it, but many people eventually become lactose intolerant in adulthood — some while they are still teens. Some health care providers view lactose intolerance as a normal human condition and therefore don’t really consider it a disease.

Who Gets Lactose Intolerance?

A person may be or may become lactose intolerant for different reasons:

  • Ethnic background. People of Asian, African, Native American, and Hispanic backgrounds are more likely to develop lactose intolerance at a young age.
  • Other problems with the digestive tract. People who have inflammation of their upper small intestine, such as celiac disease or Crohn’s disease, have a reduced level of the lactase enzyme.
  • Medicines. Certain antibiotics can trigger temporary lactose intolerance by interfering with the intestine’s ability to produce the lactase enzyme.
  • Infection. After a bout of infectious diarrhea, some kids can develop a temporary lactose intolerance that usually improves after a few days or weeks.
  • Age. As people get older, their bodies usually stop producing the lactase enzyme, and most people will naturally become lactose intolerant over time.

What Happens When Someone Has It?

People with lactose intolerance may have a variety of symptoms. It all depends on how much dairy or how many milk-containing foods the person eats and how little lactase the body produces.

Usually within 30 minutes to 2 hours after eating, someone with lactose intolerance will experience nausea, stomach cramps, bloating, gas, and diarrhea. This can be unpleasant, not to mention embarrassing if you’re at school or out with friends.

Because many people may think they’re lactose intolerant when they really aren’t, it helps to see a doctor who can diagnose the condition correctly and advise you on ways to manage it.

How Do Doctors Diagnose It?

If your doctor thinks you might be lactose intolerant, he or she will take your medical history by asking about any concerns and symptoms you have, your past health, your family’s health, any medications you’re taking, any allergies you may have, and other issues. Your doctor will also do a physical exam.

Doctors can test for lactose intolerance by using the hydrogen breath test. Normally very little hydrogen gas is detectable in the breath. However, undigested lactose in the colon ferments (breaks down) and produces various gases, including hydrogen.

If your doctor decides to give you a hydrogen breath test, you’ll be asked to blow into a tube for a beginning sample. You’ll then swallow a drink with lactose in it, wait a while, and breathe into the tube again. You’ll be asked to blow into the tube every half hour for 2 hours in order to measure hydrogen levels in your breath. The levels should go up over time if you have lactose intolerance.

Doctors also can find out if you’re able to digest lactose by testing for the presence of lactase with an endoscopy. During this procedure, doctors view the inside of the intestines by inserting a long tube with a light and a tiny camera on the end into the mouth.

A doctor can then take tissue samples and pictures of the inside of your gut and look for clues to why you’ve been having problems with what you’re eating. The amount of lactase enzyme can be measured in one of these tissue samples.

Living With Lactose Intolerance

Lactose usually can be easily managed if you’re in tune with your body. Everyone’s different, but most people with lactose intolerance can eat a small amount of dairy. The trick is to eat dairy products in combination with other foods that don’t contain lactose and not to eat too much dairy at once. It can also help to keep a food diary to learn which foods your body can or can’t tolerate.

Dairy foods are the best source of calcium, a mineral that’s important for bone growth. Because growing teens need about 1,300 milligrams (mg) of calcium each day, experts recommend that even teens who have lactose intolerance continue to include some dairy in their diet.

Foods like cheese or yogurt may be easier to digest than milk, so try a cup of yogurt for dessert or add a piece of cheese to your sandwich. Lactose-free milk is also a great way to get calcium in your diet without the problems that can come with lactose.

Taking a lactase enzyme supplement might help too. Taking this before eating foods that contain dairy will help the body digest the lactose sugar in dairy so you don’t develop the symptoms of lactose intolerance, like pain, cramping, bloating, gas, and diarrhea.

Teens with the most severe symptoms of lactose intolerance might have to avoid all dairy products. It’s extra important that these teens find other good calcium sources, so talking to a registered dietitian is a good idea. Dietitians are trained in nutrition and they can help people who are lactose intolerant come up with eating alternatives and develop a well-balanced diet that provides lots of calcium for developing strong bones.

Here are some tips for dealing with lactose intolerance:

  • Choose lactose-reduced or lactose-free milk.
  • Take a lactase enzyme supplement (such as Lactaid) just before you eat dairy products. These can be taken in drops or tablets and even added directly to milk.
  • When you do drink milk or eat lactose-containing foods, eat other non-lactose foods at the same meal to slow digestion and avoid problems. (For example, if you are going to have a milkshake, don’t drink it by itself. Have something else with it, like a healthy sandwich.)
  • Drink juices that are fortified with calcium.
  • Eat a variety of dairy-free foods that are rich in calcium, such as broccoli, beans, tofu, or soy milk. Consider hard cheeses such as cheddar, which are lower in lactose.
  • Yogurts that contain active cultures are easier to digest and much less likely to cause lactose problems.
  • Learn to read food labels. Lactose is added to some boxed, canned, frozen, and prepared foods like bread, cereal, lunchmeats, salad dressings, mixes for cakes and cookies, and coffee creamers. Be aware of certain words that might mean the food has lactose in it: butter, cheese, cream, dried milk, milk solids, powdered milk, and whey, for example.

Reviewed by: J. Fernando del Rosario, MD Date reviewed: January 2015

Can You Become Lactose Intolerant Later in Life?

It’s common to develop a lactase deficiency in adulthood. In fact, about 65 percent of the global population has a reduced ability to digest lactose after infancy, according to the National Institutes of Health (NIH).

Your genetic makeup has a lot to do with whether you’ll experience lactose intolerance. The body creates lactase when it’s instructed to do so by the LCT gene, and over time that gene can become less active. The result is lactose intolerance, which can begin after age 2 but may not manifest itself until adolescence or even adulthood, Dr. Grand says.

Some ethnic groups are more prone to developing lactose intolerance than others. According to the NIH, people of East Asian, West African, Arab, Jewish, Greek, and Italian descent are the most commonly affected by lactose intolerance in adulthood.

An injury to your small intestine — whether from an accident, surgery, radiation, infection, or disease — can also leave you unable to drink milk without symptoms, according to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Drinking poorly treated or untreated water can also cause injury to your bowel that could result in lactose intolerance, Grand adds.

Digestive Problems Similar to Lactose Intolerance

But don’t give milk the cold shoulder just yet — digestive discomfort can be caused by other conditions, especially as you get older.

Some adults think they have lactose intolerance when they really have a different gastrointestinal issue, such as celiac disease, irritable bowel syndrome (IBS), or inflammatory bowel disease (IBD), Grand says. The symptoms of lactose intolerance and these diseases, such as abdominal pain, gas, and diarrhea, can be similar. One difference between IBD and lactose intolerance is the presence of blood in your stool.

You won’t see blood if you’re lactose intolerant, but it’s possible to see blood in your stool if you have IBD.

Normal aging may make you more sensitive to digestive disturbances, such as feeling bloated after meals, Grand says. And eating certain foods that irritate the lining of the intestines or stimulate the gut to contract more quickly, such as caffeine or spicy foods, can mimic lactose intolerance symptoms.

How to Determine if You’re Lactose Intolerant

A simple way to determine whether you’ve become lactose intolerant is to completely eliminate milk and milk products from your diet and monitor how you feel in the following weeks.

“If you still have symptoms on a milk-restricted diet, you know it’s not the milk,” Grand says.

A breath test can provide a more definitive diagnosis, according to the NIDDK. For this test, you’ll drink a beverage with lactose and then breathe into a balloon-like container so that your hydrogen level can be measured. Under normal conditions, after consuming dairy, people will have only a small amount of hydrogen in their breath. If you’re lactose intolerant, you’ll produce high levels of hydrogen.

How to Manage Different Degrees of Lactose Intolerance

Some people who are lactose intolerant can still consume small amounts of milk or milk products and not feel ill, while others find their symptoms wax and wane from time to time and from food to food, Dr. Farhadi says.

Hard cheeses, such as cheddar and Swiss, contain less lactose than soft cheeses. Yogurt is also easier to digest than other forms of dairy.

Taking lactase pills or drops, such as Lactaid or Dairy Ease, before you eat can also help manage symptoms. You can also look for lactose-free alternatives to milk and milk products in your grocery store.

If you’re lactose intolerant and can’t consume any milk or milk products, Grand notes that it’s important to talk with your doctor about whether or not you should take calcium and vitamin D supplements in order to avoid developing deficiencies.

Lactose Intolerance:A Common GI Complaint

Lactose intolerance is a common GI complaint in adults. Although initially considered a “disorder”, most now consider it normal. That is, normal adults loose the ability to digest lactose. It is actually a genetic variant that allows adults to continue to produce lactase, the enzyme which breaks down lactose. If the lactose is not broken down, the typical symptoms of bloating, cramps, diarrhea, and gas occur.

So, is there a reason that a genetic variant allowing for lactase persistence would be useful? In early humans, there was no use of the enzyme beyond infancy. Early hunter gatherers had no milk in their diet. With the advent of agriculture, and domestication of animals, milk and milk products were introduced into the diet. Obviously, this would benefit only those able to break down the lactose in the milk. Research into the persistence of lactase has produced several truly amazing findings. First, there are several mutations that account for this ability that have evolved in different populations around the world. There are at least 4 gene mutations that have been found in geographically disparate populations that allow for lactase persistence. Second, this is a very recent adaption. Testing of DNA from Neolithic individuals who lived roughly 4000 to 5000 years ago has shown a very low prevalence of the mutation. This strongly suggests that there has been strong evolutionary pressure with those with the gene surviving to reproduce at much higher rates. For example, the Neolithic DNA from Sweden showed 95% of those studied were lactose intolerant, whereas the modern Swedish population has only 25% of individuals with this. Areas with a warmer climate such as around the Mediterranean and Africa have much higher rates of lactose intolerance, presumably because there was greater availability of different food sources, hence, less evolutionary pressure for the gene to spread. Isolated populations such as the Australian Aborigines, the Japanese, and Native Americans also have extremely high rates of lactose intolerance.

This is just one of many fascinating examples of how our bodies do interact with food and how rapid evolution can occur.

– GB Vogelsang, M.D.

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We’ve all been there. We’ve enjoyed our milk and cookies for dinner, then decided ice cream and a movie sounds lovely. And half way through the movie your stomach starts making audible noises, you become excessively gassy, your stomach cramps up, and you walk faster-than-normal to the bathroom to try and relieve the discomfort. It could be indigestion from the overindulgence in food. It could also be lactose intolerance. After all, near 70% of the global population is intolerant to lactose. But how? And why? Especially since breast milk is recommended food of choice for the first year of a baby’s life. Is there that much difference between cow’s milk and breast milk?

What is Lactose Intolerance?

Especially for infants, milk is seen as a complete food. Something that gives them all the vitamins, minerals, and nutrition necessary for a developing baby. As an adolescent, milk can be useful for meeting nutritional guidelines because milk contains vitamins, minerals, protein, cholesterol, and sugars. But it’s the last two ingredients that can give teens and adults problems with digestion.

Especially for infants, milk is seen as a complete food. Something that gives them all the vitamins, minerals, and nutrition necessary for a developing baby. As an adolescent, milk can be useful for meeting nutritional guidelines because . But it’s the last two ingredients that can give teens and adults problems with digestion.

Especially for infants, milk is seen as a complete food. Something that gives them all the vitamins, minerals, and nutrition necessary for a developing baby. As an adolescent, milk can be useful for meeting nutritional guidelines because. But it’s the last two ingredients that can give teens and adults problems with digestion.

The human body needs to digest foods to extract vitamins and minerals. Milk sugar, aka lactose, needs to be broken down to be digested. Milk proteins, aka casein or whey proteins, need to be broken down to be digested, too. However, not everybody digests milk or protein comfortable or at all.

How many people are lactose intolerant?

Estimates for lactose intolerance vary by ethnicity. African American and Asian ethnicities see a 75% – 95% lactose intolerance rate, while northern Europeans have a lower rate at 18% – 26% lactose intolerance. For some people, drinking milk with their morning cereal is all the dairy they need for the day. Other people have a bowl of ice cream to end the day. If the combination of those two results in stomach cramps or churning, or a 3 a.m. emergency run to the bathroom, it’s probably safe to conclude that you don’t digest cow’s milk as well as you could. Rest assured, you’re in good company.

Is Lactose Intolerance Genetically Inherited?

Genetically, you likely inherit your lactose intolerance from your parents, and they inherited it from theirs. For most people, lactose intolerance starts developing as a toddler and gets stronger as you grow up because your body reduces or eliminates the production of lactase, the chemical that breaks down the milk sugar lactase.

It’s also important to note, that when people talk about being lactose intolerant, they’re often using a collective term used to describe a few distinctly different maladies like the maldigestion, intolerance, or allergic response to cow’s milk or dairy products. Cow’s milk gets the most attention because it seems to be the major offender, with yogurts and cheeses contributing to a far lesser extent.

How Can I Tell If I’m Lactose Intolerant?

Testing for lactose intolerance can be done a few different ways; most are performed in a physician’s office or laboratory. There’s a breath test where you drink a solution of water and lactose, then wait to have your breath tested for high levels of hydrogen. It takes a couple of hours. Another option is to have a few different blood draws to see if your blood glucose levels are elevated, but this requires a few needle sticks so most people opt for the breath test. You can have your stool (aka poop) tested for acidity, have an intestinal biopsy, or have a chromatography test done on your poop. If all of these options seem complicated, well, it’s because they are. The easiest way to see if you’re lactose intolerant is to run your own test.

Consume dairy in different amounts and see how you feel 30-90 minutes after consumption. Even with lactose intolerance, most people can digest small amounts of cow’s milk without having severe symptoms. A cup of milk (eight ounces) is a good test threshold for a day’s consumption. Then see how you feel. This will give you a level for how much dairy you can tolerate in your diet. As you remain symptom free, add dairy to your diet to find your threshold. This threshold can change over time, so be aware of how your body feels after consuming dairy.

Because symptoms of lactose intolerance vary for individuals, you really need to understand what cow’s milk does to your body. Some people complain of minor symptoms like excessive amounts of gas or audible stomach churnings while others suffer more major symptoms like painful cramps or explosive diarrhea. In either case, it’s important to understand the dose response of dairy to your lactose intolerance level. And keep in mind, these things can change as you get older.

Does string cheese make your stomach upset? Probably not. Does eating an entire pizza send your stomach into fits? Maybe. Does drinking an oversized glass of milk to get more protein make your stomach cramp and your diarrhea explosive? Probably. So if you’re getting too much dairy and your body is reacting like a civil war in your stomach, you should reduce or eliminate your consumption of dairy to treat your body right. As the Physicians Committee for Responsible Medicine recommends, there is no reason for people with lactose intolerance to push themselves to drink milk.

How can I increase my tolerance of lactose products?

Some people crave milk and want it at every meal. If you’re lactose intolerant, but don’t want to give up your dairy products, you have a few options. A small lactose pill taken with a meal containing dairy can help you digest milk. Some people recommend trying to increase your tolerance to dairy products with a few simple tips. Drink milk with other foods instead of on an empty stomach so it digests easier. Consider smaller portions, then gradually increase the level of milk you drink. Try whole milk instead of skim milk because the fat can help the passage of dairy through your digestive system. Remember, too, that cow’s milk isn’t the only way to get calcium and other nutrients in your body.

Calcium-rich dairy options that aren’t cow’s milk

Going diary-free isn’t the only option for treating lactose intolerance. Hard cheeses, like cheddar, have low amounts of lactase so they can often be consumed without the side effects associated with milk. Yogurts, too, have probiotics that help with digestion. Consider goat’s milk, too, as goat’s milk is about as close as you can get to cow’s milk and comes with lower amounts of the milk protein responsible for milk allergies so it is generally more tolerated. As with all animal products, cholesterol is a concern, but lots of cow’s milk alternatives have been cropping up to help people consume lactose-free milk that doesn’t come from a cow.

Non-dairy alternatives to cow’s milk

Let’s talk about some alternatives to cow’s milk. If it comes from a plant, it’s largely better for you because you don’t get the cholesterol you’d normally find in animal products (like cow’s milk). Similar to milk in form and function, each plant milk option has a unique taste profile. Some people love the taste of almond milk. Some people find it too nutty. You’ll know after you’ve tried them for a few days and learned to grow accustomed to them.

  • Almond milk is made by grinding almonds with water and straining out the pulp. It’s high in calcium and monounsaturated fat, a heart-protecting oil, and low in calories.
  • Coconut milk is made by combining the grated meat of a mature coconut with water. It is often used in cooking recipes, and can also be used as a drink.
  • Hemp milk is made from hemp seeds soaked in water. It resembles a cream, and is often used in coffee shops as a replacement for people intolerant or allergic to cow or soy milk.
  • Oat milk is made from hulled oat grains and water. It has good nutrition and includes more calcium than a typical cup of milk.
  • Rice milk is made by milling brown rice. It’s often fortified with calcium to match the levels found in cow’s milk so you get more nutrients and a similar taste.
  • Soy milk is made by soaking dried soybeans and grinding them in water. Popular for drinking and cooking, soy milk is a popular substitute with good nutritional content.

Where can I supplement the nutrition from milk?

As with any part of your current lifestyle diet, dairy products can be removed without too much trouble. Because milk is fortified with vitamin D and is a good source of calcium, it’s important to make sure you’re getting those nutrients in your diet. The good news is that calcium is easy to get from leafy, green vegetables, protein-complete edamame or other beans or peas, nutritious fish, or other sources. If you’re meeting your nutritional needs, there isn’t a real drawback to cutting milk out of your diet. Removing cow’s milk is certainly better than suffering through the painful cramps, excessive gas, audible stomach churning, and explosive diarrhea that can accompany lactose intolerance.

So Where Do I Go From Here?

  • If you’re worried about being lactose intolerant, run your own tests to see how much milk or dairy you can consume without getting symptoms.
  • If milk is something you crave, consider buying lactase pills to take with dairy products, or trying to build up your tolerance to it with small doses.
  • Consider a diet change to find something similar to cow’s milk you enjoy, like almond milk.
  • If you have lingering questions, talk to your physician at your next appointment so they can give you personalized attention.

Find more information about lactose intolerance and Intermountain’s resources HERE.

Believe that you’re lactose intolerant?

“Fifty million Americans experience intestinal discomfort after consuming milk, cheese, or ice cream,” claims Robert Cohen, who runs the anti-dairy website called “Symptoms include stomach pain, gas, and diarrhea.”

That number is likely an exaggeration, counters Purdue University’s Dennis Savaiano, who has been studying lactose intolerance for 35 years.

“Among those who think they’re lactose intolerant, the research shows that a significant portion—anywhere between a third and three-fourths depending on the group being studied—are really not,” says Savaiano. Some of his work has been funded by the dairy industry.

“When you give them lactose disguised in a beverage so they don’t know what they’re getting, they don’t show the signs of lactose intolerance. For whatever reason, they’ve come to believe that they can’t eat dairy foods, but in fact they can.”

What the research shows

For example, a 2006 meta-analysis conducted by Savaiano and his colleagues analyzed 21 studies that gave lactose and a placebo to adults of varying ethnic groups who thought they were lactose intolerant. The participants didn’t know when they were consuming the lactose or the placebo.

The result: the amount of lactose in a cup of milk, 12 grams, did not cause any more bloating, abdominal pain, diarrhea, flatulence, or bowel movements than the placebo did.

So, many people who believe they are lactose intolerant can consume dairy foods without digestive discomfort.

The lactase enzyme

Lactose intolerance is the inability to adequately digest lactose, the sugar in milk. Infants and children have lactase enzymes in their small intestine that break lactose down into the simple sugars glucose and galactose, which are then absorbed into the bloodstream. If lactose isn’t digested in the small intestine, it passes into the large intestine, where it can draw fluid and produce gas, causing bloating and other discomfort.

Most people lose some or all of the ability to form lactase by the time they’re adults. But even if you’re an adult without lactase enzymes, the bacteria in your large intestine may still be able to digest lactose for you, says Savaiano.

“If you consume lactose regularly for a few weeks, a different metabolic capacity will develop in your colon as the microflora bacteria there adapt to digesting lactose,” he notes.

How to avoid symptoms

People who are truly lactose intolerant may be able to include dairy foods in their diet without symptoms, according to Savaiano, if they follow a few simple rules:

  • Limit lactose to no more than 12 grams (the amount in 8 oz. of milk) at a time.
  • Consume lactose with other foods to slow down the transit of the sugar through your intestines and give it more time to be digested.
  • Eat dairy foods regularly so that your intestinal bacteria remain adapted to digesting lactose.

Yogurt has about 10 grams of lactose per cup (the yogurt’s bacteria help digest the lactose). A serving of hard cheese or cream cheese has a gram or less, while a half cup of cottage cheese or ice cream has 4 to 5 grams.

Why try to work dairy into your diet?

“People who avoid dairy foods usually don’t compensate by consuming other sources of dietary calcium,” says Savaiano.

Sources: J. Nutr. 136: 1107, 2006; Am. J. Clin. Nutr. 64: 232, 1996.

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